Process for cleaning metal.



H. E. FINLAY & E. L. FANGBONER. PROCESS FOR CLEANING METAL.

APPLlCATlON FILED JUNE 8. 19!].

Patented Jan 14,1919.

INVENTORS 3 2 ATTORNEYS more snares PATENT orator.

HERBERT E. FINLAY, OF DETROIT, AND FRANK LEROY FANGBONER, OF ROYAL OAK, MICHIGAN, ASSIGNORS TO BURROUGHS ADDING MACHINE COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

PROCESS FOR CLEANING METAL.

Application filed June 8, 1917.

To all whom it may concern:

Be it known that we, HERBERT E. FINLAY and FRANK LEROY FANGBONER, citizens of the United States, and residents of Detroit, WVayne county, Michigan, and Royal Oak, Oakland county, Michigan, respectively, have invented certain new and useful Improvements in Processes for Cleaning Metal, of which the following is a specification.

Our invention is designed more particularly to provide for cleaning machine constructions and parts and removing rust therefrom. Prior to our invention it has been common to pickle metal parts in a solution of hydrochloric acid or the like for the purpose of removing rust and subsequently washing the same as a preliminary to coating the articles with a plating metal, enamel, or the like. In some instances the bath in hydrochloric or muriatic acid has been followed by a dipping in nitric acid, but this separate step has the disadvantage that it leaves the metal in a discolored condition. Whether the muriatic acid alone or muriatic and nitric acid are employed the acid penetrates the pores of the metal, is not thoroughly removed by the subsequent water bath and ultimately causes the article to rust. Furthermore, where the article treated is partially or entirely nickeled or japanned the above described pickling processes are open to the objection that they tend to cause the nickel or enamel, as the case may be, to drop off.

In our improved process the acid bath or pickling is followed by a bath in cyanid of potash or the like which neutralizes any acid present and thereby counteracts the tendency to rust due to the acid working out of the pores of the metal after treatment. Other features of our invention will be understood from the drawings accompanying and forming part of this application and the following detailed description thereof. It is to be understood, however, that the specific disclosure is for the purpose of exemplification only and that the scope of the invention is defined in the following claims in which we have endeavored to distinguish it from the prior art so far as known to us without, however, relinquishing or abandoning any portion or feature thereof.

Referring to the drawings, Figure 1 is a Specification of Letters Patent.

Patented Jan. 14, 1919.

Serial No. 173,449.

diagrammatic view of the apparatus employed by us, the elements thereof being for the most part shown in transverse vertical section; and Fig. 2 is a perspective view of a detail.

The tank 3 may be of any suitable material not attacked by the liquid which it is intended to receive and has a cover 4 thereon. A rotating table 5 is journaled on the spindle 6 in a bearing 7, such spindle being provided with a beveled gear 8 meshing with a similar gear 9 on a horizontal shaft 10. The shaft 10 is driven by a pulley 11 and belt 12 from any suitable source of power. The table is designed to receive the article to be treated. Within the chamber or tank 3 is located a device for spraying the machine carried on the rotating table, said device comprising a coupling 13 connected to an inlet pipe 14 through a valve 15, a U-shaped pipe 16 partially surrounding the rotating table, and a series of perforated upright pipes 17, 18. The pipes 17 are provided at their tops with branch perforated pipes 19 arranged to practically form a circle, and perforated on their inner sides, each of said perforated pipes being adapted to direct streams of liquid upon the article upon the table. At 20 is shown a draw-off pipe by which the liquid after being sprayed upon the article to be treated, is returned to the supply tank. The liquid injected into the tank or chamber 3 is preferably a solution of Sal-soda (bicarbonate of soda) which may be in the proportion of one-half pound of the salt to one gallon of water. The solution is maintained at a temperature of about 150 Fahrenheit and injected under considerable pressure against the machine or other article to be cleansed, and the latter is subjected to the treatment for from three and one-half to five minutes by which all of the grease upon the machine is thoroughly dissolved and removed.

After the alkaline treatment above described the article is dipped in a solution of muriatic acid and water, preferably in the proportions of two and one-half gallons of water to thirty seven and one-half gallons of ordinary commercial muriatic acid, the resulting solution showing a specific gravity of approximately fifteen degrees Baum. After the solution of muriatic acid has been made, as indicated above, we add one quart of nitric acid which gives the desirable bright finish to the metal. The immersion in the acid bath is only momentary, this being sufficient to permit the acid to act upon any oXid upon the metal parts of the machine or other article being treated. Preferably the acid tank is kept at a ten'iperature of about 110 Fahrenheit, and for this purpose the acid solution is contained in an earthenware tank 21, which is immersed iii a tank 22 containing water. The tank 22 is supplied with water through a pipe 23 and faucet 2 and maintained at the desired temperature by injection of steam into the water through a. pipe 25 perforated as at 26 at its lower end which extends upon the bottom of tank 22. An overflow pipe 27 maintains the proper level of the water in tank 22. Obviously by thecombined use of the cold water supply and the st am injection the ten'iperature of the water in the tank 22 can be kept within the desired limits. \Vhen it is desired to empty the water tank, this may be done. by simply removing the overflow pipe 27 which is tapered and titted into a corresponding seat 28 in the bottom of the tank.

From the acid bath the metal articles are next transferred to a. tank 25) supplied with cold water through a spigot 30 connected to pipe 23, the water being maintained at the desired level by an overflow pipe 31 similar to overflow 27. The metal articles having been washed in the cold water of tank 29 are next immersed in a cyanid solution contained in an earthenware tank 32 \within tank 29. Tank 32 contains a. solution of cyanid of potassium of a specific gravity of 20 Baum. The metal articles are immersed in this bath for a period of about three minutes, permitting the cyanid to neutralize the acid which the metal contains, thus preventing the rusting which would otherwise occur.

' From the cyanid bath the articles are re turned to tank- 3 and given another wash ing in a sal soda solution from 3% to 5 min utes to remove the cyanid from'the metal. They are then immersed in a hot water tank 33, the water in which is heated by a steam coil 34 through which the steam is or may be continuously circulated. At 35 is shown a trap for said coil. The cover 36 closes the tank and the level of the .water therein is determined by the overflow pipe 37. The

water in this tank is maintained at approximately 150 Fahrenheit, and the articles are immersed therein for a period of one minute to remove the soda. J

The articles are next immersed in a bath of hot oil 38 contained in a steam-jacketed kettle 39. The steam is supplied to the jacket of said kettle by the pipe 4L0 and condensation is drawn off through pipe 41. A steam trap 42 is interposed in the pipe ll and a. by-pass provided by which the water of condensation may when desired be carried by said trap by opening the valve 44. The oil is maintained at a temperature between 260 and 280 Fahrenheit whereby any water is vaporized and the metal is partially lubricated by hot oil.

From the hot oil bath the articles are conveyed to a tank-45 which contains cold oil in which they are dipped and by which the metal isthoroughly lubricated to prevent rust.

It will thus be seen that. by our improved process and apparatus the meta] articles are thoroughly cleaned, pickled, neutralized and lubricated in such manner that all tendency to the formation of rust is overcome. If the metal article is in part coated with another metal, enamel or the like. the coating is not in any way interfered with by the treatment to which the article is subjected.

\Ve claim:

1. A method of cleaning metal articles and removing rust therefrom which consists in pickling them in an acid solution and then immersing them in a cyanid solution whereby the acid is neutralized.

2., A method of cleaning metal articles and protecting them froin rust which consists in subjecting them. to muriatic and nitric acids and then to a solution of cyanid.

3. A process of cleaning metal articles and protecting them from rust which consists in subjecting them to a mixture of muriatic and nitric acids and then to a solution of a cyanid.

4. A method of cleaning metal articles and protecting them from rust which consists in first subjecting them to a hot solution of muriatic and nitric acids and then to a cold solution of a cyanid.

5. A process of treating metal articles for cleaning them and preventing rust which consists in pickling the articles, then subjecting them to a solution of a cyanid, washing them, and imm'ersin them in oil heated to a temperature above t at of boiling water.

6. A process of treating metal articles for cleaning the same and protecting them from rust which consistsin pickling said articles, washing them and subjecting them successively to a bath of oil heated above the boiling temperature of water and a relatively I cold bath of oil.

HERBERT E. FINLAY. FRANK LEROY FANGBONER. 

